The present invention relates to an inverter in which two switching elements serially connected to a direct current power source are complementarily controlled to turn on and off, and more specifically it relates to an inverter control circuit provided with delay circuits on respective control signal paths for switching elements which delay circuits are aimed at delaying respective rise times of the on-control signals by a preset amount.
In an inverter of the type that a plurality of switching circuits, each circuit comprising serially connected switching elements, are connected parallel to a direct current power source, and that independent of each switching circuit, the switching element at the positive voltage side and the switching element at the negative voltage side as viewed from the direct current power source are complementarily controlled to turn on and off, delay circuits heretofore have been provided on control signal paths for delaying respective rise times of the on-control signals by a preset amount, in order to prevent a short circuit of the power source and the breakage of the switching element itself resulting from the concurrent turning on of both switching elements.
However, each delay circuit is a combined circuit of a charge/discharge circuit made of a capacitor, a resistor, and a diode, and a NOT circuit. Therefore, the delay circuit is under the influence of the scattering in rated values of elements and the ambient temperature change. Thus, it is required to design the circuit so as to have a sufficient margin, which results in setting an off-time remarkably long. This leads to various problems such as the lowering of an output voltage of the inverter.